1. Field of the Invention
The present invention relates to a dial plate structure and an automotive meter.
2. Description of the Related Art
Dial plates for automotive meters include an index portion and a ground color portion that forms a background for the index portion. The index portion and the ground color portion are generally formed through printing on a substrate, so that the dial plate is viewed planarly.
A known technique that causes the dial plate to be viewed three-dimensionally uses a previously printed flat substrate that is deformed by protruding molding or drawing to thereby form an inclined surface or irregularities on the dial plate. This technique allows the dial plate surface to have a three-dimensional look.
The technique is not, however, suitable for three-dimensionally molding only a limited area on which the index portion is formed and, unfortunately, is not capable of molding the index portion into a sharp form, as noted by the substrate being rounded for curvature of the wall thickness thereof.
A dial plate structure has been developed that further enhances design appearance of an automotive meter. The dial plate structure includes a three-dimensional scale disposed on an illuminating light guide member disposed beneath a dial plate. The three-dimensional scale protrudes from a through hole open at a corresponding portion in the dial plate, thus constituting a three-dimensional scale structure (see Japanese Patent Application Laid-open No. 2003-106873).
The pointer instrument disclosed in Japanese Patent Application Laid-open No. 2003-106873 includes, as illustrated in FIGS. 6A to 6C, a pointer and an indicating plate (dial plate) 501 to be indicated by the pointer. The indicating plate 501 is disposed to have a circularly arcuate arrangement format along the rotational path of the pointer. The indicating plate 501 includes an index portion 503 to be pointed by the pointer and a ground color portion 505 that assumes a background for the index portion 503. The index portion 503 includes scale portions 507 and indicia portions 509 associated with the scale portions 507.
The ground color portion 505 includes a first ground color portion 511 and a second ground color portion 513. The first ground color portion 511 is formed into a band shape along the scale portions 507 to thereby form a background for the scale portions 507. The second ground color portion 513 is formed around the first ground color portion 511, part of the second ground color portion 513 forming a background for the indicia portions 509.
The indicating plate 501 has openings (through holes) 515 that correspond to the scale portions 507. An indicating member (light guide) 517 is disposed at the back of the indicating plate 501. The indicating member 517 includes a base portion 519 that extends in a band shape along a back surface of the indicating plate 501 and protruding portions 521 that protrude toward the side of the indicating plate from the base portion 519 (see FIG. 6C). The protruding portions 521 protrude on the indicating plate from the openings 515 to thereby form part of the scale portions 507. The protruding portions 521 are provided in plurality, each having an outline shape corresponding to the internal shape of the corresponding opening 515 in the indicating plate 501. A coloring layer 523 is formed on the surface of each of the protruding portions 521.
The foregoing arrangements result in the protruding portions 521, each having a three-dimensional structure protruding on the indicating plate, being visually recognized as a three-dimensional scale corresponding to the scale portions 507 of the indicating plate 501.
The above-described dial plate structure that includes the index portion 503 in the openings 515 formed at a corresponding portion of the indicating plate 501 is, however, very often provided with a dial plate back surface print (print layer) 525, such as a design print and a dimming print, on the back surface of the indicating plate 501, as illustrated in FIG. 7. It is noted that a print void portion 527 of, for example, a numeral may be formed according to the indicia portions 509 for the dial plate back surface print 525. Such a dial plate back surface print 525 is generally soft. If the protruding portions 521 have an angular shape, therefore, the dial plate back surface print 525 may be damaged when the indicating member 517 is mounted on the back of the indicating plate 501 to thereby cause the protruding portions 521 to protrude on the indicating plate through the openings 515. It is difficult to simultaneously fit the protruding portions 521 into the respective openings 515. Meanwhile, use of an assembly jig, for example, can minimize damage, but results in reduced workability and increased manufacturing cost.